Guard for spring locks



p 22, 1954 L. T. Ma LAUGHLlN ETAL 3,149,870

GUARD FOR SPRING LOCKS Filed June 18, 1962 INVENTORS Loews Tao Mac. LAUGHl-IN OsaoRue L. BULLERWELL BYM$AEQQ ATTORN EYS United States Patent 3,149,870 GUARD FOR SPRING LOCKS Lucius Ted MacLaughlin, 202 Minor North, Seattle 9, Wash, and Osborne L. Bullerwell, 1161 John St., Seattle, Wash.

Filed June 18, 1962, Ser. No. 203,222 1 Claim. (Cl. 292-346) The present invention relates to a device for safeguarding doors having locks of the springbolt type in which the projecting end of the bolt has a beveled face for engaging a strike plate preliminary to entering a keeper.

Frequently, as time goes on the crack between the swinging edge of a door and the related jamb grows wider thereby exposing the bevel face of the bolt. Then it becomes relatively easy for a burglar to insert a knife blade, shim-stock, celluloid card, etc. and press thereby against the exposed bolt face, and because of its bevel, force the bolt to retract from the keeper. Accordingly, the present invention has as its principal object the providing of a simple and inexpensive guard which can be easily installed on the door jamb to prevent such tampering with the bolt of an existing spring lock and which can be readily adjusted for vairous widths of gaps between the door and jamb.

With yet additional objects and advantages in View which, with the foregoing, will appear and be understood in the course of the following description and claims, the invention consists in the novel construction and in the adaptation and combination of parts hereinafter described and claimed.

In the accompanying drawings:

FIGURE 1 is a fragmentary horizontal sectional view illustrating a conventional spring-lock in operating position before use of our invention.

FIG. 2 is a side elevational view of a blank piece of sheet metal prior to forming into the guard of the present invention along folds indicated by broken lines.

FIG. 3 is a front elevational view of the completed guard.

FIG. 4 is a view taken as in FIG. 1, but with our device safeguarding position.

FIG. 5 is a vertical sectional View taken as indicated by line 55 in FIG. 4.

FIG. 6 is a fragmentary horizontal sectional view showing the mounting position of a modified guard.

Referring to the drawings, the door 10 is shown fitted with an exposed spring lock 11 whose case 12 is screw mounted on the indoor face of the door. A turnable knob 13 is jcurnaled in the case for retracting a latch bolt 14 which is conventionally spring-urged into a keeper 15. The latter is cast integral with a strike plate 16 having a flat extension 17 morticed into the door jamb 18 and anchored thereto by screws. A beveled face 20 is provided on the outer end of the bolt 14 which, while the door is being closed, engages the indoor edge of the strike plate and is thereby retracted sufficiently to clear and thereupon project into the cavity 21 of the keeper. In this manner the swinging side of the door is held between the latch bolt and a stop bead 22 provided by the jamb 18. The structure thus far described does not comprise part of the present invention and may take a great variety of forms.

As previously mentioned, the described type of latch frequently can be easily forced open by inserting a thin flexible object between the door and stop bead 22, forcing it to bend into the gap 23 between the door and the jamb 17, and then pushing it against the beveled bolt face 29 so that the resultant pressure retracts the bolt. Someimes the burglary tool can be forced directly between the stop bead and the jamb into the door gap Patented Sept.-22,'1964 "ice to gain access to the latch bolt. In either instance the burglar is aided if the door gap 23 has expanded since original installation of the door as is commonly the case in older structures.

The present invention comprises a guard 24 which is fabricated from a sheet (FIG. 2) of thin flexible malleable metal or plastic material, such for example as aluminum, to present a flat mounting plate 25 having a pair of longitudinally spaced screw openings 26 which are spaced apart in excess of the length of the strike plate 16. The blank for the guard is cut transversely adjacent the ends of one of its edges as indicated at 2929 to define top and bottom tabs 27-28 and a central stop flange 30. This flange is bent back at 31 to form an acute dihedral angle with the mounting plate 25, and this angle can be readily manually adjusted.

The guard 24 is mounted on the jamb 17 by screws 32 in centerd overlapping relation to the anchor portion of the strike plate 16 and with the bend or root edge 31 of its stop flange 30 within the door gap 23 adjacent the plane of the indoor face of the door when closed. Then the stop flange is adjusted so that it substantially traverses the width of the door gap. This adjustment can be easily made by first covering the projecting edge of the stop flange with a sheet of paper with one hand while slowly closing the door with the other. In this manner as the door closes it will engage and bend the stop flange back toward the mounting plate 25 the proper amount for door clearance while the paper protects the lead edge of the door against scufling by the stop flange 30. When this adjustment is completed the tabs 27-28 are manually twisted in the door direction on diagonals 27a-28a at about a forty-five degree angle so as to occupy positions directly above and beneath the portion of the latch bolt which is exposed between the case 12 and the strike plate 16 as determined by the door gap. This twisting adjustment of the tabs is made such that the free ends of the tabs project away from the plane of the mounting plate 25 about the same amount as the free longitudinal edge of the stop flange 30.

With the described arrangement the stop flange 30 prevents a burglar tool from being forced opposite the latch into the door gap and pressed against the bolt face 20 to spring the lock. At the same time the end tabs 27-28 prevent an L-shaped burglar tool from being first inserted endwise of the stop flange and then lowered or raised between the stop flange 30 and the bolt face 20 for engagement with the latter.

In FIG. 6 I have shown a modified guard 24a in which the tabs 27-28 have been eliminated. This guard is mounted such that the stop flange 30 occupies a position against the bevel face 20 of the bolt 14 when the door 10 is closed rather than in the door gap 23 as before. In this modified position the flange 30 prevents insertion of a burglarly tool from above or below as well as directly through the gap.

It is thought that the invention will have been clearly understood from the foregoing detailed description. Changes in the details of construction will suggest themselves and may be resorted to without departing from the spirit of the invention, wherefore it is my intention that no limitations be implied and that the hereto annexed claim be given a scope fully commensurate with the broadest interpretation which the employed language admits.

What We claim is:

A guard for spring locks comprising a mounting plate adapted to be secured to a door jamb in the gap between the jamb and the swinging edge of the door directly outdoors of the bolt of the related lock, and a stop forming an acute dihedral angle with said plate bendable with respect to the latter at the apex line of said angle to adjust said angle whereby the guard will traverse said gap for preventing the passage of the burglary tool through the gap from the outdoor side of the door to the bolt, and end tabs projecting away from said mounting plate at said apex line and bendable with respect to said mounting plate to project indoors of said stop to occupy positions directly above and below the portion of said bolt exposed by said gap for preventing access by a burglary tool to the bolt from above or below References Cited in the file of this patent UNITED STATES PATENTS Scott Sept. 8,

Henry Dec. 17,

FOREIGN PATENTS Great Britain Nov. 1,

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